The present invention relates to the utilization of rotary vane pumps to achieve an efficient mixing action. More specifically, it primarily relates to the utilization of such pumps to achieve an efficient mixture between a liquid such as water and a gas mixture such as a gas mixture containing a high proportion of ozone.
It is commonly recognized that pumps of virtually all types can be utilized to mix two different fluids together. The mixing action normally achieved with virtually any type of a pump is a result of a turbulence occurring during pump operation. Frequently, such turbulence is inadequate to achieve a desired degree or amount of mixing between two different fluids. This can be illustrated by referring to a common use of rotary vane pumps in mixing two different fluids.
As such pumps are used for this purpose, the two different fluids are normally passed to the interior of the pump through a common inlet. As a pump of this type is operated, a rotor within a stator is turned so as to cause vanes carried by the rotor to move outwardly from the rotor against an eccentric wall so as to create a partial vacuum tending to pull the fluids into the pump. Then, as rotor rotation continues the fluids which have been drawn into the pump are compressed between the eccentric wall and the rotor as the vanes move inwardly until finally they are forced under pressure from within the interior of the pump. This type of action involves considerable physical turbulence and it also involves application of mechanical pressure to the two fluids being mixed.
Unfortunately, this mixing action is not normally sufficiently effective when used with a liquid and a gas to create a solution or dispersion of the gas in the liquid containing as high a proportion of the gas as desired. It is considered that the reasons for this in part relate to the degree or amount of shearing action achieved between the liquid and the gas in a rotary vane pump of the type described. It is also considered that in part this may be the result of the manner in which the two fluids--i.e., a liquid and a gas--are normally brought into contact with one another in a conventional rotary vane pump as indicated.
The relative ineffectiveness of conventional pumps and especially rotary vane pumps in creating a satisfactory mixture of a liquid and a gas is becoming increasingly important as there is increasing recognition of the desirability of forming such mixtures. This can be illustrated with reference to the utilization of ozone. Ozone is normally produced by treating ambient air in an appropriate field so as to convert normal molecules of oxygen into ozone molecules. The gas mixture resulting from such treatment contains all of the gases normally found in ambient air and, in addition, ozone. Although such a gas mixture can be utilized directly for many purposes, it is frequently desired to utilize a mixture of such a gas mixture and a fluid such as water.
In such a mixture the ozone is normally utilized as an oxidizing agent. Thus, for example, a mixture of ozone and water is frequently formed so that the ozone will oxidize impurities within the water. For such a mixture to be effective for oxidizing purposes over a prolonged period it is considered that the ozone should be taken up into the water as by absorption and/or by the formation of exceedingly small bubble-like regions which will not readily separate from the water. The effectiveness of any such mixture and/or solution in causing oxidation is of course dependent upon the proportion of the ozone within the liquid and the time required for such ozone to either break down and/or otherwise escape from the liquid.
In the past, when pumps have been utilized to create intimate mixtures of two fluids such as, for example, an intimate mixture of water and a gas mixture containing ozone, it is not considered that the items in the mixture have been adequately admixed with one another to the extent necessary for the final mixture to be relatively stable and to contain a high proportion of the gas mixture. It has frequently been desired to utilize essentially known types of pumps in creating such mixtures because the techniques of designing and manufacturing such pumps are reasonably well established and because many types of pumps are available at a comparatively nominal cost. Also, when a pump is utilized in forming a mixture as indicated, the pump serves two functions--it forms a mixture as indicated and also it provides a physical force necessary to convey the mixture formed to a desired location.